The present invention relates to a refrigerator provided with an evaporator for a refrigerator compartment and an evaporator for a freezer compartment.
A refrigerator provided with a refrigerator compartment and a freezer compartment, each compartment is equipped with a dedicated evaporator in some refrigerators of recent years. These refrigerators have a freezing cycle, as shown in FIG. 13.
In the freezing cycle 100 of FIG. 13, a condenser 103 is connected to the downstream side of a compressor 102, which is divided at its downstream into two branches. To one branch, there are connected a refrigerator compartment change-over valve (as will be abbreviated into the xe2x80x9cR-valvexe2x80x9d) 104, a refrigerator compartment capillary tube (as will be abbreviated into the xe2x80x9cR-capixe2x80x9d) 106 and a refrigerator compartment evaporator (as will be abbreviated into the xe2x80x9cR-evaxe2x80x9d) 108. To the other branch, there are connected a freezer compartment change-over valve (as will be abbreviated into the xe2x80x9cF-valvexe2x80x9d) 110, a freezer compartment capillary tube (as will be abbreviated into the xe2x80x9cF-capixe2x80x9d) 112, a freezer compartment evaporator (as will be abbreviated into the xe2x80x9cF-evaxe2x80x9d) 114 and a check valve 116. Moreover, the conduits from the check-valve 116 and the R-eva 108 circulate through the compressor 102.
On the other hand, an R-fan 118 is provided for feeding the air cooled in the R-eva 108 to the refrigerator compartment, and the F-eva 114 is equipped with an F-fan 120.
In the aforementioned freezing cycle 100, the prior art control method will be described with reference to FIG. 14.
In this control method, a refrigerating run (as will be abbreviated into the xe2x80x9cR-modexe2x80x9d) for cooling the refrigerator compartment and a freezing run (as will be abbreviated into the xe2x80x9cF-modexe2x80x9d) for cooling the freezer compartment are alternately carried out. When the refrigerator compartment reaches a predetermined temperature, specifically, the R-valve 104 is opened, but the F-valve 110 is opened to feed the refrigerant to the F-eva 114 thereby to establish the F-mode. When the freezer compartment reaches a predetermined temperature in the F-mode, on the other hand, the F-valve 110 is closed, but the R-valve 104 is opened to feed the refrigerant to the R-eva 108 thereby to establish the R-mode.
Here, the R-eva 108 and the F-eva 114 are different in evaporation temperature and in the calorie of evaporation enthalpy. If both the R-eva 108 and the F-eva 114 have a necessary cooling calorie of 40 W, therefore, the refrigerant flow rate in the R-eva 108 is twice as high as that of the F-eva 114 because of the difference in the calorie of the evaporation enthalpy. In other words, when the evaporation temperature rises from a low level to a high level, the necessary refrigerant flow rate is raised by the difference in the specific suction capacity of the compressor 102.
This difference in the refrigerant circulation rate between the R-eva 108 and the F-eva 114 causes the delay in the refrigerant behaviors at the transition from the F-mode to the R-mode. For the first reason, the refrigerant flowing at rate of 1 in the F-mode has to flow at a rate of 2 when the mode is switched to the R-mode. For the second reason, the compression ratio of the compressor 102 is high in the F-mode but falls in the R-mode, so that the refrigerant is reluctant to flow into the R-eva 108 due to the difference in the compression ratio.
Moreover, the aforementioned delay in the refrigerant behaviors triggers to establish the state, in which anywhere but the entrance portion of the R-eva 108 is not cooled, as shown in FIG. 13. There arises a problem that the exit or its vicinity is not cooled to a necessary temperature so that the sufficient cooling capacity is not exhibited. This problem affects the cooling capacity adversely.
On the other hand, the refrigerant, as has been stagnant in the F-eva 114, cannot flow to the compressor 102 when in the R-mode at the high pressure. As a result, the refrigerant circulation is so lessened as cannot be adjusted. Therefore, the flow rate of the refrigerant circulation in the freezing cycle 100 changes for each run. Moreover, this change causes a more delay in the refrigerant behaviors.
From the problems thus far described, there arise problems that the refrigerant circulation cannot be correctly controlled, and that the cooling ability cannot be correctly controlled.
In view of the foregoing problems, therefore, the invention contemplates to provide a refrigerator which can control the refrigerant circulation correctly and can reduce the delay in the refrigerant behaviors.
According to the invention, there is provided a refrigerator comprising: a compressor and a condenser connected in the recited order; an evaporator for a refrigerator compartment and an evaporator for a freezer compartment both connected in parallel to the downstream side of the condenser, and switching unit interposed between the condenser and the two evaporators for switching the passage for a refrigerant from the condenser, between the refrigerator compartment evaporator and the freezer compartment evaporator; and a condenser fan for cooling the condenser, a cold air circulation fan for the refrigerator compartment for blowing the cold wind of the refrigerator compartment evaporator to the refrigerator compartment, and a cold wind circulation fan for a refrigerator compartment for blowing the cold air of the refrigerator compartment evaporator to the freezer compartment, whereby a refrigerating run for cooling the refrigerator compartment by feeding the refrigerant to the refrigerator compartment evaporator and a freezing run for cooling the freezer compartment by feeding the refrigerant to the freezer compartment evaporator can be individually executed by switching the passage of the refrigerant by the switching unit, wherein at the end of the freezing run, a refrigerant recovery run for recovering the refrigerant from the refrigerator compartment evaporator and feeding it to the condenser is performed by running the compressor while blocking the refrigerant to flow to the freezer compartment evaporator with the switching unit and by running the condenser fan; and after this refrigerant recovery run, the refrigerating run is performed by switching the switching unit to feed the refrigerant only to the refrigerator compartment evaporator.
In a refrigerator according to the invention, after a predetermined time from the start of the refrigerant recovery run, the refrigerating run is performed by switching the switching unit to feed the refrigerant only to the refrigerator compartment evaporator.
In a refrigerator according to the invention, after the temperature of the freezer compartment evaporator reaches a predetermined level after the start of the refrigerant recovery run, the refrigerating run is performed by switching the switching unit to feed the refrigerant only to the refrigerator compartment evaporator.
In a refrigerator according to the invention, after the refrigerating run was performed by switching the switching unit to feed the refrigerant only to the refrigerator compartment evaporator, the cold air circulation fan for the refrigerator compartment is run when the temperature of the refrigerator compartment evaporator falls to a set level.
In a refrigerator according to the invention, when the compressor is to be stopped from the freezing run or the refrigerating run, a stop preparatory run for recovering the refrigerant from the freezer compartment evaporator or the refrigerator compartment evaporator to feed the refrigerant to the condenser is performed by running the compressor while switching the switching unit to block the refrigerant to be fed to the freezer compartment evaporator or the refrigerator compartment evaporator, and by running the condenser fan at a low speed, and after the stop preparatory run, the compressor and the condenser fan are stopped while the refrigerant to be fed to the freezer compartment evaporator or the refrigerator compartment evaporator being blocked by the switching means.
In a refrigerator according to the invention, after a set time from the start of the stop preparatory run, the compressor and the condenser fan are stopped while the refrigerant to be fed to the freezer compartment evaporator or the refrigerator compartment evaporator being blocked by the switching means.
In a refrigerator according to the invention, after the drive current value of the compressor became lower than a set level from the start of the stop preparatory run, the compressor and the condenser fan are stopped while the refrigerant to be fed to the freezer compartment evaporator or the refrigerator compartment evaporator being blocked by the switching means.
In a refrigerator according to the invention, the switching unit includes two two-way valves.
In a refrigerator according to the invention, the switching unit includes a three-way valve.
According to the invention a refrigerator includes a compressor and a condenser connected in the recited order; an evaporator for a refrigerator compartment and an evaporator for a freezer compartment both connected in parallel to the downstream side of the condenser, and switching unit interposed between the condenser and the two evaporators for switching the passage for a refrigerant from the condenser, between the refrigerator compartment evaporator and the freezer compartment evaporator; and a condenser fan for cooling the condenser, a cold air circulation fan for the refrigerator compartment for blowing the cold wind of the refrigerator compartment evaporator to the refrigerator compartment, and a cold wind circulation fan for a refrigerator compartment for blowing the cold air of the refrigerator compartment evaporator to the freezer compartment. Whereby a refrigerating run for cooling the refrigerator compartment by feeding the refrigerant to the refrigerator compartment evaporator and a freezing run for cooling the freezer compartment by feeding the refrigerant to the freezer compartment evaporator can be individually executed by switching the passage of the refrigerant by the switching unit. The refrigerator also including a block unit for blocking the refrigerant to flow to the refrigerator compartment evaporator and the freezer compartment evaporator; and a refrigerant recovery run for recovering the refrigerant to feed it to the condenser is performed by running the compressor while the refrigerant to flow to the refrigerator compartment evaporator and the freezer compartment evaporator being blocked by the block unit, and by running the condenser fan.
In a refrigerator according to the invention, the refrigerant recovery run is performed either when it is determined that the refrigerant is short in the refrigerator compartment evaporator or the freezer compartment evaporator or at the switching time when the refrigerating run and the freezing run are alternately performed.
In a refrigerator according to the invention, the speed of the compressor at the refrigerant recovery run is, continued from that of the compressor, which was set at the refrigerating run or at the freezing run before the transition to the refrigerant recovery run.
In a refrigerator according to the invention, the running time of the refrigerant recovery run is set the longer for the lower speed of the compressor.
In a refrigerator according to the invention, the running time of the refrigerant recovery run is set the longer for the lower ambient temperature.
In a refrigerator according to the invention, the refrigerant recovery run is stopped when the temperature of the refrigerator compartment evaporator or the temperature of the freezer compartment evaporator is lower than a set level.
In a refrigerator according to the invention, an accumulator is provided on the downstream side of the refrigerant of the refrigerator compartment evaporator, and the refrigerant recovery run is stopped when the temperature of the accumulator becomes lower than a set level.
In a refrigerator according to the invention, either the cold air circulation fan for the refrigerator compartment at the refrigerating run before the transition to the refrigerant recovery run or the cold air circulation fan for the freezer compartment at the freezing run is continuously rotated.
In a refrigerator according to the invention, the cold air circulation fan for the refrigerator compartment or the cold air circulation fan for the freezer compartment is stopped when the temperature of the refrigerator compartment evaporator and the temperature of the freezer compartment evaporator exceeds a set level.
The operations of the refrigerator of the present invention are described as follows.
When the freezing run is to be switched to the refrigerating run, at the end of the freezing run, the compressor is run while blocking the refrigerant to flow to the refrigerator compartment evaporator, and the condenser fan is also run.
As a result, the refrigerant from the freezer compartment evaporator is recovered and fed to the condenser, and this refrigerant is also liquefied by running the condenser fan, thus ending the refrigerant recovery run.
After this refrigerant recovery run, the switching unit is switched to feed the refrigerant only to the refrigerator compartment evaporator thereby to perform the refrigerating run. Thus, it is possible to prevent the delay in the refrigerant behaviors.
As the refrigerant recovery run, the control is made on the basis of the set time, or the refrigerating ran is started when the temperature of the freezer compartment evaporator reaches the set level.
The operations of the refrigerator of the present invention are described as follows.
After the refrigerating run was performed by switching the switching unit to feed the refrigerant only to the refrigerator compartment evaporator, the cold air circulation fan for the refrigerator compartment is run when the temperature of the refrigerator compartment evaporator falls to a set level. In other words, the cold air circulation fan is stopped at the time of starting the refrigerating run. Then, the liquid refrigerating run, as has been stagnant in the condenser, easily flows to the R-eva.
The operations of the refrigerator of the present invention are described as follows.
When the compressor is to be stopped from the freezing run or the refrigerating run, the stop preparatory run is performed, and the compressor and the condenser fan are then stopped while the refrigerant passages to the individual evaporators being blocked by the switching unit.
As a result, the liquefaction of the refrigerant can be promoted by recovering the refrigerant from the freezer compartment evaporator or the refrigerator compartment evaporator to feed it to the condenser and by running the condenser fan at a low speed.
Thus, the refrigerant easily flows to the evaporator at the next return of the compressor, so that the refrigerant delay can be eliminated.
On the other hand, the time for the stop preparatory run is controlled with the set time or ended when the current value for driving the compressor becomes lower than a set level.
Moreover, the switching unit can be exemplified by two two-way one or one three-way valve.
According to the invention, it is possible to adjust the balance between the refrigerants stagnant in the refrigerator compartment evaporator and the freezer compartment evaporator thereby to feed the refrigerants in proper amounts to the refrigerator compartment evaporator and the freezer compartment evaporator, thereby to suppress a useless increase in the input.
According to the invention, it is possible to eliminate the refrigerant delay, as might otherwise be caused when it is determined that the refrigerant in the freezer compartment or the refrigerator compartment is short or after the run was switched. Thus, the cooling can be performed efficiently while exploiting the performance of each evaporator sufficiently, to shorten the time period before the steady state is reached.
According to the invention, the control is facilitated, and the complicated fluctuation in the compressor speed is suppressed to reduce the noises.
According to the invention, the refrigerant can be recovered in a substantially proper amount by the simple control.
According to the invention, the proper amount of refrigerant can be recovered by the simple control even when the ambient temperature changes.
According to the invention, the excessive refrigerant recovery can be prevented to suppress the deterioration in the reliability of the compressor.
According to the invention, the cold heat in the evaporator, as might otherwise be cooled in an endothermic manner at the refrigerant recovery, can be circulated in the compartment so that the cooling effect of the circulation fan can be made effective to make a contribution to a constant temperature.
According to the invention, the input increase, as might otherwise be caused by excessively driving the circulation fan, can be suppressed to effect a more efficient cooling.